Failure of 0.51 Cuben

If this tarp was used properly and not abused( and it does not sound like it) , then it needs to be sent to Joe V for credit towards a new tarp. And then he should send it to Dyneema and ask them to do a better job making their product:)

80 usage cycles simply is not acceptable for a product that costs several hundred dollars..

I have a 0.51 cuben rain cover from ZPacks that I have had for several years. Last year I noticed some spots that looked similar to that, however, my pack cover was subject to a bit of abrasion at times. For example, during rains when the pack cover was on, when I took the pack off, I usually laid it on the front of the pack, or on the rain cover. However, I was always careful to set it in an area with little amount of objects to cause abrasion, such as grass or leaves. I would imagine that due to this, some holes were rubbed in the material, so I did as the OP stated and used some cuben tape to repair the areas. I also have a Hexamid cuben tarp, however I have not witnessed any areas like this on it, although, I have never really looked that hard… I will get mine out and set it up to check it out soon though as I have a week long trip coming up. I have not had mine out quite as much though… only about 30 – 40 nights total.

Yes, this does seem to happen with the very light stuff. Remember: it was made for use as a sail, not as a waterproof fabric for outdoors use, so sustained waterproofness was not in the design spec.

What is happening is that every time the fabric is folded/crinkled/packed, the extra stress on the Mylar membrane causes a weakness which eventually breaks down. This is especially common at places where there is a fold in two directions. Obviously, that does not matter in a sail as it still works as a sail. The heavier grades of Cuban last longer, but they too will eventually break down in the same way. Basically, Cuban is a short-life product, unlike silnylon.

Cheers (or otherwise)

Basically, Cuban is a short-life product, unlike silnylon.

I believe the vertices of the UL shelter Triple Constraint are Minimal Weight, Waterproof and Durable  :)

I wonder how much of it is due to exposure to the sun. I have some well used and thin Cuben sacks that look better than the OP’s picture.

“This topic has been reported for inappropriate content”

What? Why?

“What? Why?”

Cuben blasphemy?

Maybe someone hit the button by mistake?

The buttons should prompt an “are you sure”.

Here is Ron’s (MLD) comment on .52 cuben: ”
<p class=”p1″><span class=”s1″>”We also offer some of your smaller Mids and tarps in a lighter .5oz sq/yd cuben. It will have a shorter service life and is good for 3+ season use.” (Shorter compared with .75 cuben)</span></p>

personally im too lazay to have to babii gear … but thats me

;)

Anybody know why the .5 cuben should have a shorter lifespan than. 75 cuben? As I understand it, they both have the same thickness of mylar so I would expect them to both remain waterproof for the same amount of time.

I’d estimate (I don’t keep logs or records) that my Duplex with .51 Cuben, purchased in 2014, has about as many nights on it as the OP’s, although with very minimal heat and UV exposure. Later this morning I’m starting an overnight hike and will be sleeping in the Duplex tonight. I’ll look very closely to see if anything like this is present.

That would indeed be a bummer.

I’m thinking the “inappropriate content” was a double mis-lick. If not, I’d like to know why, just for the fun element. :^)

William, Well, as I understand it the heavier weight stuff uses a heavier weight reinforcing thread (usually a form of spectra.) This would cause a little less of a “sharp” crease when folded, leading to less breakage of the plastic layers due to stress differentials between the inside and outside layers.

It was me who hit the “inappropriate content” button, sorry! I’m using a touch screen iPad and it’s too easy to hit things. No “are you sure” second chance either.

Given the location of the problem is by the spot with the highest stress, any damage to the fibers that happens there, is bound to cause something like that. To me, the design of the hexamid shelter, is going to be prone to that happening eventually; even with the .75 stuff. I’ve talked to 2 different hexamid owners who had a similar thing happened though their shelters weren’t as old but had heavier use.  I also wouldn’t expect .51wt stuff to last 4+ years either.

The reason my first cuben fiber 0.6wt (1st gen stuff) MLD cat. tarp lasted almost 8 years, is in part, due to the point of most stress being the long ridge line where the 2 side panels are doubled up. This is much better at distributing the stress out then a single high point like the hexamid. Even then, the material of my tarp eventually broke down in other ways as it started to allow water to soak through and suffered abrasion and pin holes on the panels as the fibers got damaged. Because of the lack of real stress there, the holes didn’t try to enlarge. I certainly don’t expect my new 0.5 tarp to last nearly as long though since it’s a lighterweight material.

“I wonder how much of it is due to exposure to the sun.”

Perhaps some, but part of the reason why mylar was chosen as the sandwiching material for this sail material, is because out of all the commonly used synthetics, it’s one of the few that handle UV pretty well.  Mylar is basically the same thing as polyester and it stands up to UV innately much better than nylon, polypropylene, UHMWPE, LDPE, HDPE.

Only thing which is better in this regard, is silicone, but thin films are not made out of it to my knowledge.

A silicone coating on the outside of cuben will help to further increase it’s UV handling properties, reduce some abrasion wear, increase HH, and increased slickness would make it better for snow use.

+1 to what Miner said.

Thread has been ‘un-reported’.

Cheers

Back from my little overnight trip and am happy to report I did not observe a problem similar to the OP’s… merely a tiny bit of creep with the seam sealing tape and reinforcing cup adhesive.

Photo of the reinforcement cup region of the ridgeline, and a cropped section of that photo…

So I will remain vigilant and try not to be too paranoid about it! :^o

And also interested to learn what others find if/when similar inspections are done.

josh ….

one thing i didnt see people ask is which side are these holes appearing in … are they on the door side, etc … if they are only on one side it could be a stress point

bob …

with 2 poles on a duplex perhaps theres less stress vs a single pole hexamid?

;)

if they are only on one side it could be a stress point

I doubt it has anything to do with stress. It is all to do with damage at the creases. We have been here before.

Cheers

bob …

with 2 poles on a duplex perhaps theres less stress vs a single pole hexamid?

Hmm… I’ll have to think about the mechanics of that!

One thing’s for sure, I have never pitched it extremely tautly, “tight as a drum”. I just don’t think it’s necessary, and my Duplex has seen high winds only a handful of times, so there’s that. And IMO leaving any tent pitched all day and exposed to UV light is not a good idea. I recall well getting a stern warning about this from none other than Jack Stephenson when I picked up my Warmlite at his shop in NH.

Not picking nits here, just saying that’s how I do things and so far, so good. I don’t expect the thing to last forever, anyway.

A 0.75 hexamid I recently purchased had this sort of damage near the front corner stake out points. Zpacks provided repair tape for the damage. The tent was purchased for a friend and he is happy with the resolution. The tent I purchased was also 2012 vintage.

Perhaps 2012 was not a good year for cuben?

On a related note, when I queried Zpacks regarding the storage of cuben tents I was told using the stuff sack was just fine. Someone above stated folding cuben could cause the damage found by the OP.  Urban legend our reality?

My 0.74 Duplex, November 2013 vintage, so far shows no signs of similar wear/damage. I *have* pitched it “drum tight” on occasion while battening down the hatches during strong winds. Bob’s experience of that being unnecessary makes me question whether I will continue that practice in the future.  Certainly under normal circumstances a drum-tight pitch is not required and in fact, with the doors open may not even be possible.